I don't think this will happen. Doesn't Six Flags have a few neglected parks already (Six Flags America and Six Flags St Louis come to mind)? Best to take care of those before they build another park.
Also, Six Flags has only built 3 parks in their history (SFOG, SFOT, and SFSL), and that was in the early years. Nowadays, Six Flags doesn't actually build parks; they buy them.
If anything, I can see Six Flags building a park in North Florida (Jacksonville, Tallahassee, etc). Even then, given the current condition of the company, I don't think they'll be building or buying a park for a looong time...